1. Field of the Invention
The present invention relates in general to a molecular recognition sensor system and process of making same which can be used for the detection of different chemicals in both the liquid and gaseous states and, more particularly, to a sensor device based on a molecular imprinted conducting polymer in nanoscale and process of making same.
2. Description of Related Art
Numerous methods and devices exist for the chemical detection of analytes. For example, prior art methods have attempted to detect analytes by imprinting analyte molecules into a polymer. These methods employ arranging polymerizable monomers around a template followed by polymerization and template removal. The result is a polymer having cavities of the same size and shape as the analyte. The transduction methods detecting the binding of the analytes into the cavities created in the polymer can be electrical, electrochemical, or optical etc, which measure the resistance/conductance, electrochemical properties and optical absorption of the imprinted polymer. See e.g. Polymer-Based Lanthanide Luminescent Sensor For Detection Of The Hydrolisis Product Of The Nerve Agent Soman In Water, Jenkens, et al., Anal. Chem. Vol 71, p. 373-378 (1999), Molecularly Templated Materials in Chemical Sensing, Ellen L. Holthoff, Frank V. Bright, Analytica Chimica Acta Vol 594, p. 147-161 (2007) and Progress in the Development of Molecularly Imprinted Polymer Sensors, Arnold, et al., Johns Hopkins APL Technical Digest, Vol. 20, No. 2 (1999) incorporated herein by reference.
U.S. Pat. No. 6,807,842 discloses a molecular recognition sensor system for detecting the presence and concentration of an analyte including a resistive sensor having a semi-conductive polymer film which swells when exposed to an analyte and interferents, together with a molecular imprinted resistive sensor having a semi-conductive polymer film imprinted with the analyte. The resistivity of the film is monitored during sensing to detect any changes in the resistivity of the film produced by the presence of an analyte.
In this system, the polymer film imprinted with an analyte swells when exposed to interferents. A circuit connected to the resistive sensor and the molecular imprinted resistive sensor detects a change in the resistance of the molecular imprinted resistive sensor when exposed to the analyte and interferents, and subtracts the change in the resistance of the molecular imprinted resistive sensor from the change in resistance of the resistive sensor to reduce the effect of any interferents on the change and resistance of the resistive sensor, thereby determining the presence and concentration of the analyte.
The resistivity of the semi-conductive polymer film is monitored during sensing. However, molecular imprinted polymer films often suffer long response time due to the limitation of diffusion. Also the sensitivity of the film sensor is limited because the lateral current shunting reduces the resistance change.
U.S. Pat. No. 7,384,589 discloses a nanoscale molecular imprinted polymer. However, the process of forming the polymer is complex, using a laser source for photoinitiation to produce nanoscale polymer features. The conventional imprinting process is time consuming and complicated by the use of cross-linkers. Further, the fabrication process restricts the detection methods to fluorescence and surface enhanced Raman spectroscopy, which increase the cost of the operation due to the integration of the optical components.
U.S. Patent Application Serial No. 20060207878 discloses conducting polymer nanowire sensors. One dimensional conducting polymer nanowires are defined with electron beam lithography and fabricated using electrochemical polymerization. The analyte-binding species and analyte are restricted to antibody-antigen, protein, polynucleotide and DNA. These sensors can be sensitive and selective. However, both the fabrication and the biological species for binding are expensive. Furthermore, biological binding restricts the future application.
Nevertheless, these molecular imprinted polymer devices suffer from the distinct disadvantage that they are designed to be specific to only one target analyte, are large, bulky, complex, delicate, and difficult to use.
It is therefore an object of this invention to provide a molecular recognition sensor system and method of using same.
It is another object of this invention to such a molecular recognition sensor system and method which can accurately detect an analyte.
It is a further object of this invention to provide such a molecular recognition sensor system and method which can accurately detect the concentration of an analyte.
It is another object of this invention to provide such a molecular recognition sensor system and method which can detect a plurality of analytes.
It is a further object of this invention to provide such a molecular recognition sensor system and method which can detect a plurality of analyte concentrations.
It is another object of this invention to provide such a molecular recognition sensor system and method which can detect a plurality of analyte in liquid and gaseous phases.
It is yet another object of this invention to provide such a molecular recognition sensor system which is compact, inexpensive, and easy to use.
It is a further object of this invention to provide such a molecular recognition sensor system which is simple in design and easily transportable.